In a medical institution such as a hospital, conventionally, a dry preparation such as a powdery drug or a freeze-dried drug, which is held in a drug container such as a vial, is used while being dissolved in a solvent or the like in an injection syringe. The resultant drug solution is used as an infusion for drip injection. Such a drug loses its efficacy in a state of a drug solution and, consequently, can not be stored in the state of the drug solution.
However, the mixing of the drug into the solvent by means of the injection syringe is a complicated process that requires time and effort, and has the following problem. That is, there is a possibility that the drug held in the vial is contaminated.
It is considered herein that a drug to be used for drip injection has a toxic property. In a case of a dried state, the toxic drug, which is held in a container such as a vial, is used in a form of a drug solution prepared by means of an injection syringe or the like and then is coinfused in an infusion container. In a case of a liquid state, on the other hand, the toxic drug is directly sucked into and collected by the injection syringe and then is coinfused in the infusion container. However, the coinfusion using the injection syringe is a complicated process that requires time and effort. Upon preparation of the toxic drug, moreover, in a state that a pressure is applied to a connection portion of the injection syringe irrespective of a level thereof or in a state that a hydraulic pressure in the infusion container is applied to the connection portion of the injection syringe, removal of the injection syringe causes a possibility that a splash or spill or the drug solution occurs at the connection portion. In the occurrence of splash or spill or after drying of the splashed or spilled solution, an aerosol generates and floats in the air. Such an aerosol is exposed in an ambient environment for a long period of time and causes the following problem. That is, there is a possibility that the aerosol exerts an adverse influence on health of medical staffs and patients.
In order to solve this problem, Japanese Patent Laying-Open No. 7-8555 proposes a pre-filled syringe. This pre-filled syringe includes a barrel filled with a solvent, a cylindrical communication supporting tool attached to an outer wall of a tip end of the barrel, and a communication means supported by the communication supporting tool. Herein, a vial attaching part is provided on the communication supporting tool and a communication means supporting part is provided below the communication supporting tool.
As an example of a tool for coinfusion in the infusion container, Utility Model Publication No. 49-3187 or Utility Model Publication No. 53-30152 proposes a solution collecting device. This device includes: a needle main body of a solution collecting needle, having a drug solution communicating inner cavity formed at a center in a longitudinal direction and an air and drug solution infusing groove formed at a side wall in the longitudinal direction; a covering body having a branched tube protruding from a lower side thereof so as to be communicatively connected to the air and drug solution infusing groove, the covering body being used for covering the needle main body; and a cylinder body formed into a spherical shape or a shape similar thereto using a flexible material such as rubber or soft plastic in order to allow the air and the drug solution to pass only in an infusing direction, the cylinder body being provided with a check valve including a hollow valve part having a slit formed at a front side thereof and a hollow conduit part made of a material similar to that of the valve part and integrated with the valve part, the cylinder body being suitably fit into the branched tube.
It is considered that a toxic drug is used in this device. In such a case, first, a drug solution is introduced into an infusion container and is diluted without fail in the infusion container. Therefore, there is no possibility that the drug solution is administered in a high toxic state as a concentrate. Moreover, this device allows prevention of backflow of the drug solution to be coinfused and, therefore allows suppression of a risk that the toxic drug is exposed in an ambient environment from a connection portion of an injection syringe. In addition, this device brings about an advantage that no injection needle is required.
However, the solution collecting device still has a possibility that the drug solution existing in a space formed between the check valve and a nozzle of the injection syringe is spilled upon removal of the injection syringe. Further, the integrated drip barrel hinders free selection of an infusion set, which causes increase in cost of the solution collecting device in some instances. Even when the space formed between the check valve and the nozzle of the injection syringe is made small as much as possible, there is a possibility that the liquid solution is drawn from the nozzle of the injection syringe and a spill of the drug solution occurs due to the following reason. That is, at an instant that the nozzle of the injection syringe is removed, the space is in a low pressure state temporarily.
In order to solve the problems of the solution collecting device described above, National Patent Publication No. 2005-522281 discloses the following device. That is, this device includes an inlet port which receives a first medical fluid, an infusion port through which a second medical fluid is infused, an outlet port which serves as an outlet of a mixed flow of the first and second medical fluids, a first duct which extends between the infusion port and the inlet port, and a second duct which extends between the inlet port and the outlet port. Herein, when the second medical fluid is infused, the infusion port is sealed with a fluid impermeable film through which an injection needle can penetrate. Thus, this device includes at least a first portion made of a first material and a second portion made of a second material. Herein, the second material is substantially higher in elasticity than the first material. The first portion includes the inlet port and the infusion portion, and the second portion includes the outlet port. The first and second portions are attached to each other by complex friction coupling and snap connection offering a first retention force.
According to this device, a toxic drug is infused only when the injection needle penetrates through the fluid impermeable film of the infusion port. Therefore, the toxic drug can be safely administered by drip without being exposed in the outside air. In a case where a fluid transferring device is attached to the nozzle of the injection syringe, particularly, a film is also attached to a tip end of the fluid transferring device. Therefore, safety is secured after cancellation of the connection because an outer face of the needle is not exposed to the outside.    Patent Document 1: Japanese Patent Laying-Open No. 7-8555    Patent Document 2: Utility Model Publication No. 49-3187    Patent Document 3: Utility Model Publication No. 53-30152    Patent Document 4: National Patent Publication No. 2005-522281